A duck is a species of bird that mostly lives in water. The spell Ducklifors is used to turn organisms into ducks.

A rubber duck is a type of bathtub toy, shaped in the likeness of a duck, that is fairly common in Muggle society, but may be rare in the wizarding world.

During the Infiltration of the Ministry of Magic, Harry Potter overheard an employee of the Muggle-Born Registration Commission mention an episode involving a poisonous duck apparently created by the Committee on Experimental Charms.